To assist in navigation in an airport, a process of taxiing typically includes receiving a clearance from an air traffic controller (ATC), checking the received clearance, entering the received clearance into a navigation system for displaying the clearance on a map, and building a taxi route from a current position to a destination position, for example, on a runway or at a parking gate.
In preparation for the taxiing, flight crews perform several tasks. The crews determine an accurate position of the aircraft by observing its external surroundings and/or a map. Then, the crews find and monitor a taxiing path based on the ATC clearance while monitoring an outside events and movements for preventing collision with other aircraft or equipment. Further, the crews prepare the aircraft for optimizing the taxiing path according to ATC constraints. As a result, the workloads of the flight crews become significant and convoluted during airport surface operations.
It is important that the taxiing operation is performed smoothly without any interruptions and delays. An optimization of the taxiing operation, for example, from the runway to the gate (i.e., taxi-in) and from the gate to a line-up on the runway (i.e., taxi-out), is also critical for the efficiency of the airline and airport operations. Today, certain conventional applications are provided for an effective taxing operation, but these applications are not accurate enough and are data/time consuming.
As an example, an airport database specification developed by an Aeronautical Radio, Incorporated (ARINC), namely ARINC 816, defines an embedded interchange format for Airport Mapping Database (AMD). The ARINC 816 standard proposes a way to describe airport elements, such as taxiways, runways, parking areas, stands, buildings, roads, obstacles, and the like. Specifically, ARINC 816-0 provides geometrical descriptions with points, lines and polygons used for displaying airport maps on on-board displays. ARINC 816-2 provides additional objects, such as nodes and edges (or links between two nodes) for describing a flow graph of the airport.
Further, the ATC provides a taxi clearance to the flight crews via radio or datalink communication services. The taxi clearance includes information about a departure point, successive airport elements, and a destination point in a particular order. Specifically, the taxi clearance has a set of airport element names indicating the departure and destination points, and any elements therebetween (e.g., E60 (via) P10 P40 W30 (to) 14L, where E60 denotes the departure point, 14L denotes the destination point, and P10, P40, and W30 denote the successive elements). Based on this taxi clearance, a taxi route is entered into an on-board avionics system using a keyboard, a datalink, or other suitable electronic devices (e.g., a color-coded electronic chart developed by Jeppesen®). The taxi route represents an on-ground trajectory of the airport, including a set of identifiers or a set of point coordinates, continuously connecting two extremities (e.g., the departure and destination points).
In the aircraft, an ownship position is determined by various sensors, such as an Inertial Reference System (IRS) or a Global Navigation Satellite System (GNSS), or some radio navigation devices (VHF Omnidirectional Range, Distance Measuring Equipment) or any combination of above-mentioned systems and devices. The ownship position is typically displayed on the on-board avionics system for navigation purposes, and provides a map which represents the aircraft surroundings within a predetermined range. To generate the taxi route, the flight crew receives the taxi clearance and writes it on a piece of paper. Next, the crew uses an airport paper map to find the taxi route to follow.
Alternatively, the crew uses the Jeppesen® chart to highlight a path on a digital map as if the crew draws the path with a pen, but the pilot must enter the clearance into the system using the keyboard or other suitable tactile interactive devices for computing the corresponding taxi route on the digital map for display. This manual process of entering the sequence is slow and cumbersome because the clearance needs to be continuous (i.e., each clearance element must be connected to a successive one). For example, if the taxi clearance sequence is long, ensuring the continuity of the clearance sequence takes time when using the keyboard. Further, aircraft characteristics, such as its Aircraft Classification Number (ACN), maximum limitations concerning its wingspan, and its Pavement Classification Number (PCN) are not included in computing the taxi route.
Generally, the flow graph of the airport is described through the nodes and edges, which are tightly integrated with other geometrical objects. For example, the nodes and edges are attached to containers, which contain objects related to a given element. A runway container contains a runway surface geometry, a runway center line geometry, runway thresholds, runway markings, nodes and edges related to this particular runway, and the like. Thus, the flow graph of the airport includes unnecessary geometrical descriptions of the airport, causing memory space waste, longer computation time, and redundant complexity for generating the taxi route. Further, because this type of flow graph does not include an explicit connectivity of each edge, the associated application must determine to which set of edges a given edge is connected, thereby causing additional computation time. Typically, this type of flow graph only includes taxiways and runways, and does not have parking apron and deicing areas, making it impossible to compute the taxi route from or to a gate or a parking stand.
Another disadvantage of the conventional application is that when a system of visualization of the taxi clearance is available in the cockpit via the avionics system or an Electronic Flight Bag (EFB) system, the flight crews often must use a piece of paper to write down the clearance before entering the clearance into the system, and explicitly advise the avionics system that the pilot will manually enter the clearance. Modern tactile tablets, such as iPad® or laptops with a touch-sensitive screen, can support the EFB system for managing documents, aircraft libraries, manuals, and the like. However, the drawback of Component On-The-Shelf (COTS) tablets is that a GNSS position provided by the tablets does not satisfy mandated accuracy required in the aviation rules and regulations, such as a general acceptable means of compliance for airworthiness of products, parts and appliances, namely AMC 20-25.
All these steps take additional time and increase workload during the taxiing operation while the pilot simultaneously performs other tasks, such as checking and controlling the aircraft, communicating with ground personnel, performing surveillance tasks, and the like. These additional tasks can be a source of potential errors, and may require significant time and effort to correct mistakes while listening to ATC instructions, thereby increasing operation costs. Therefore, there is a need for developing an improved taxiing system and method such that the taxiing system facilitates an accurate guidance of the aircraft for reliable on-ground navigation and control, using a standardized airport database.